0 <=> 0 	> 0
0 <=> 2 	> -1
3 <=> 0 	> 1

0 <=> 0 	> 0
0 <=> 2 	> -1
3 <=> 0 	> 1

fi <=> fi 	> 0
fi <=> se 	> -1
th <=> fi 	> 1
